Wood preservatives

ABSTRACT

Wood preservatives contain a copper compound, an alkanolamine, a triazole, an emulsifier and/or a phosphonium compound and are used for impregnating wood.

This application is a division of application Ser. No. 08/785,084, filedon Jan. 21, 1997, now U.S. Pat. No. 5,853,766, which is a continuationof application Ser. No. 08/329,425, filed on Oct. 24, 1994, now U.S.Pat. No. 5,635,217, which is a continuation of Ser. No. 07/860,155,filed on Mar. 30, 1992, now abandoned.

Wood preservatives based on inorganic copper compounds withalkanolamines as complexing agents are known (European Patent 89,958).Despite high copper contents, the activity of these agents againstwood-destroying Basidiomycetes is insufficient in comparison with knowncopper- and chromate-containing salts having a comparable coppercontent.

It has now been found that wood preservatives based on copper compoundsand alkanolamines, which contain a triazole compound and an emulsifieror which contain a phosphonium compound, have very good activity againstwood-destroying Basidiomycetes. The present invention relates tomixtures which contain a triazole compound and an emulsifier, tomixtures which contain a phosphonium compound and to mixtures whichcontain a triazole compound, an emulsifier and a phosphonium compound.

In spite of the content of copper compounds in the wood preservative, ondilution with water the triazole compounds form a clear emulsion. Theadvantage of the novel agents is that triazole compounds which areinsoluble in water are present in the novel agents in the the form ofaqueous emulsions or clear aqueous concentrates. Clear aqueous liquidsare formed on dilution with water.

Homogeneous concentrates can be obtained by adding small amounts oforganic solvents to the wood preservative, for example alcohols (ethanolor isopropanol), glycols (ethylene glycol or propylene glycol), glycolethers (ethylene glycol monomethyl ether or ethylene glycol monoethylether), glycol ether esters (butylglycol acetate), dimethylformamide orN-methyl-pyrrolidone. The solvents additionally act as solubilizers forthe triazoles. With the additional use of arylcarboxylic acids,cycloalkylcarboxylic acids or aliphatic C₅-C₂₀-mono- or dicarboxylicacids or corresponding amine, alkali metal or copper salts, however, theuse of solvents can be reduced to a minimum for obtaining homogeneousconcentrates.

The copper compounds can be used as water-soluble or water-insolublecompounds, for example copper sulfate, copper acetate, copper hydroxide,copper oxide, copper borate, copper fluoride or basic copper carbonate.

An alkanolamine is, in particular, monoethanolamine; the use of otheralkanolamines, for example isopropanolamine, 1,1- or 1,2-diaminoethanol,aminoethylethanolamine, diethanolamine, triethanolamine ormethylethanolamine, is possible.

The amount of added alkanolamines is advantageously such that a pH of 7or more, preferably from 8.5 to 10.5, is established in the diluteaqueous impregnating solution. The amount of amines should be sufficientfor complexing the copper (1 g atom of copper requires about 4 molequivalents of amine).

A triazole compound is, for example,1-(2-(2,4-dichlorophenyl)-4-methyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole,1-(2-(2,4-dichlorophenyl)-1,3-dioxolan-2-ylmethyl)-1H-1,2,4-triazole(azaconazole),1-(2-(2,4-dichlorophenyl)-4-ethyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole,1-(2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole(propiconazole),1-(2-(2,4-dichlorophenyl)-4-phenyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazoleor α-tert-butyl-a-(p-chlorophenylethyl)-H-1,2,4-triazole-1-ethanol(tebuconazole).

An emulsifier is, for example, an anionic, cationic or nonionicemulsifier or a mixture thereof. Nonionic emulsifiers are, for example,adducts of ethylene oxide (EO) or propylene oxide or mixtures thereofwith organic hydroxy compounds, for example alkylphenols, fatty acids,fatty alcohols and mixtures thereof. Examples of suitable cationicemulsifiers are quaternary ammonium compounds and/or salts of fattyamines (for example dimethyl-(C₁₂-C₁₄)-alkylamines).

A quaternary ammonium compound is, for example, a compound of thegeneral formula R¹R²R³R^(4N) ⁺Z⁻, where R¹ is alkyl of 8 to 20 carbonatoms, in particular alkyl of 12 to 20 carbon atoms or benzyl which isunsubstituted or substituted by C₁-C₂₀-alkyl or halogen, R² isC₁-C₆-alkyl, C₃-C₉-alkoxyalkyl or polymeric ethylene oxide (EO) orpropylene oxide (PO) where the number of EO or PO units n is from 2 to50, R³ is C₁-C₆-alkyl, C₃- or C₄-alkoxy or polymeric ethylene oxide (EO)or propylene oxide (PO) where the number of EO or PO units n is from 2to 50 and R⁴ is C₁-C₂₀-alkyl, or two of the radicals R¹ to R⁴, togetherwith the nitrogen atom, form a heterocyclic radical which contains 4 or5 carbon atoms and one, two or three double bonds, the carbon atomsbeing unsubstituted or substituted by C₁-C₄-alkyl or halogen, and Z isan acid radical, eg. halide.

Particularly suitable phosphonium compounds are compounds of the formula

R¹ ₃R²P⁺Y⁻

where R¹ is alkyl of 1 to 6 carbon atoms, hydroxyalkyl of 1 to 6 carbonatoms or phenyl, R² is alkyl of 8 to 18 carbon atoms and Y is an acidradical, in particular a halide anion.

R¹ and R² are preferably straight-chain.

The quaternary phosphonium compounds may be present individually or asmixtures in the novel concentrates. Examples of such phosphoniumcompounds are trimethyl-n-dodecylphosphonium chloride,triethyl-n-decylphosphonium bromide,tri-n-propyl-n-tetradecylphosphonium chloride,trimethylol-n-hexadecylphosphonium chloride,tri-n-butyl-n-tetradecylphosphonium chloride,tri-n-butyl-n-dodecylphosphonium bromide, tri-n-butyl-n-decylphosphoniumchloride, tri-n-butyl-n-hexadecylphosphonium bromide,tri-n-hexyl-n-decylphosphonium chloride, triphenyl-n-dodecylphosphoniumchloride, triphenyl-n-tetradecylphosphonium bromide andtriphenyl-n-octadecylphosphonium chloride.

Aliphatic carboxylic acids can be added to improve the homogeneity ofthe concentrates. Examples of such acids are propionic acid, hexanoicacid, heptanoic acid, branched carboxylic acids, eg. 2-ethylenehexanoicacid or isooctanoic acid, neocarboxylic acids, aliphatic dicarboxylicacids, eg. sebacic acid, cycloalkylcarboxylic acids, eg. cyclohexanoicacid, and arylcarboxylic acids, eg. benzoic acid or 3- or4-hydroxybenzoic acid.

When the abovementioned acids are used, it is advantageous in some casesto improve the penetration of the wood preservative in large scaleindustrial processes by adding complex-forming, polymeric nitrogencompounds, eg. polyethyleneimines.

Polyethyleneimines (PEI, polymin) are known and are formed bypolymerization of 1,2-ethyleneimine. They contain the nitrogen inprimary (terminal group), secondary or tertiary (branching) form.Polyethyleneimines where n is greater than 10 are suitable; very goodresults are obtained when PEI having a degree of polymerization nbetween 50 and 1,000 are used.

The wood preservatives may, if required, contain further compounds, forexample compounds having a fungicidal anion, such as a boron compound(for example alkali metal borate, aminoborate, boric acid or boricester) and fluorides (for example potassium fluoride and/or salts offluoboric acid and/or fluophosphoric acid and/or difluophosphoric acid).

The action spectrum of the novel wood preservatives can, if required, beimproved by adding further active ingredients. Examples of suitablecompounds are N-organodiazeniumdioxy compounds, organotin compounds, inparticular tributyltin (TBT) compounds and isothiazoline compounds ofthe following formula

where R¹ is hydrogen, an alkyl, alkenyl or alkynyl radical of 1 to 18carbon atoms, cycloalkyl having a C₃-C₆-ring and not more than 12 carbonatoms or an aralkyl or aryl radical of not more than 19 carbon atoms andR² and R³ independently of one another are hydrogen, halogen orC₁-C₄-alkyl, or R² and R³ are part of an aromatic radical.

It is also possible to add further fungicides or insecticides, forexample in emulsified form, such as N-tridecyl-2,6-dimethylmorpholine(tridemorph) and/or4-(3-para-tert-butylphenyl)-2-methyl-propyl-2,6-cis-dimethylmorpholine(fenpropimorph) and/or chlorinated phenolstetrachloroisophthalodinitrileN-cyclohexyl-N-methoxy-2,5-dimethylfuran-3-carboxamideN-dimethyl-N′-phenyl-(N-fluoromethylthio)-sulfamideN,N-dimethyl-N′-toluyl-(N-fluoromethylthio)-sulfamide methylbenzimidazole-2-carbamate 2-thiocyanomethylthiobenzothiazole2-iodobenzanilide 1-(1′, 2′,4′-triazol-1′-yl)-1-(4′-chlorophenoxy)-3,3-dimethylbutan-2-one 1-(1′,2′, 4′-triazol-1′-yl)-1-(4′-chlorophenoxy)-3,3-dimethylbutan-2-olhexachlorocyclohexaneO,O-diethyldithiophosphorylmethyl-6-chlorobenzoxazolone2-(1,3-thiazol-4-yl)-benzimidazoleN-trichloromethylthio-3,6,7,8-tetrahydrophthalimideN-(1,1,2,2-tetrachloroethylthio)-3,6,7,8-tetrahydrophthalamideN-trichloromethylthiophthalimide 3-iodo-2-propylbutyl carbamateO,O-dimethyl S-(2-methylamino-2-oxoethyl) dithiophosphate O,O-dimethylO-(3,5,6-trichloro-2-pyridyl) thiophosphate O,O-dimethylS-(N-phthalimido)-methyl dithiophosphate O,O-diethylO-(α-cyanobenzylideneamino) thiophosphate6,7,8,9,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,3,4-benzodioxothiepene3-oxide (4-ethoxyphenyl)-(dimethyl)-3-(4-fluoro-3-phenoxyphenyl)-propylsilane 2-sec-butylphenyl N-methylcarbamate 2-propoxyphenylN-methylcarbamate 1-naphthyl N-methylcarbamate norbornenedimethanohexachlorocyclosulfite1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)-urea synthetic pyrethroids,such as 3-phenoxybenzyl(+)-3-(2,2-dichlorovinyl-2,2-dimethyl)-cyclopropane-1-carboxylateα-cyano-3,3-phenoxybenzyl3-(2,2-dichlorovinyl-2,2-dimethyl)-cyclopropane-1-carboxylate3-(2,2-dibromovinyl-2,2-dimethyl)-α-cyano-m-phenoxybenzyl(1R,3R)-cyclopropanecarboxylate (deltamethrin)α-cyano-3-phenoxybenzylisopropyl-2,4-chlorophenyl acetate.

In concentrated form, the water-dilutable wood preservatives generallycontain the copper, for example, in an amount of from 1.0 to 15.0% byweight, calculated as metal.

Suitable concentrates consist of, for example,

from 2.50 to 45%, in particular 10 to 20%, of copper compounds,

from 5.00 to 50%, in particular 20 to 40%, of alkanolamine,

from 0.25 to 15%, in particular 1 to 10%, of triazole compounds,

from 2.50 to 40%, in particular 10 to 20%, of phosphonium compounds,

from 0.5 to 30%, in particular 5 to 15%, of an emulsifier,

from 0 to 40% of a compound having a fungicidal inorganic or organicanion,

from 0 to 40% of an organic solvent,

from 0 to 40% of an aliphatic mono- or dicarboxylic acid and/orcycloalkylcarboxylic acid and/or cycloarylcarboxylic acid and

from 0 to 15% of a complex-forming, polymeric nitrogen compound,

the sum being 100% by weight in each case, and, if required, minoramounts of other components, for example ammonia, corrosion inhibitors,complex-forming acids (eg. nitrilotriacetic acid orethylenediaminetetraacetic acid where water of relatively high hardnessis used) and, if required, water, the amount of which however cangenerally be kept small and which essentially serves handling purposes.

In addition to the wood preservatives (concentrates), the presentinvention also relates to the impregnating solutions of correspondinglylower individual concentration which can be prepared by diluting theconcentrates with water. The application concentration corresponds to,for example, from 0.01 to 1.50% by weight of metal, eg. copper, in theaqueous impregnating solution, depending on the method of impregnationand the level of risk to which the wood to be impregnated is exposed.

Dissolving the copper salts, if necessary with heating, in thealkanolamines, with or without the addition of acid, water or solvents,and subsequent addition of the emulsifier, the triazole compounds and/orphosphonium compounds result in the formation of highly concentratedpastes, liquid concentrates or two-phase mixtures which, after dilutionwith water, can be used for impregnating wood. They give a clear liquidin water, even at a high concentration.

The impregnating solution can be used for preserving wood by manualmethods, such as spraying, brushing on, immersion or troughimpregnation, or by large-scale industrial processes, such as thepressure process, alternating pressure process or double vacuum process.Wood is understood both as solid wood and as woodworking materials, suchas particle boards or plywood; here, the wood preservative may also beintroduced in the glue mixing process.

The degree of fixing of the copper in the novel preservatives is high;it is more than 90% when large scale industrial methods are used.

The concentrates or solutions can be colored by water-soluble orwater-emulsifiable dyes and/or pigment preparations.

Wax, paraffin and/or acrylate dispersions may be added to achieve awater-repellant effect or to improve the fixing.

The concentrates can, if required, also be incorporated inbinder-containing water-dilutable systems (primers or transparentcoats).

The Examples which follow illustrate the invention.

Determination of the limit of action against wood-destroying fungi

The method is used for determining the preventive action of woodpreservatives against wood-destroying fungi.

Identical wooden blocks (5×2.5×1.5 cm) dried to a constant weight at103° C. are completely impregnated with stepwise amounts of the woodpreservative to be tested and are dried, washed thoroughly with water(washing out the active ingredient mixture from the wood) and exposed toattack by cultures of wood-destroying fungi in glass dishes. Thenutrient medium used for the fungi is malt agar (containing 4% of maltextract). The destruction of the wood caused by the fungal attack ismeasured by the weight loss of the wood specimens; a weight loss of 2%or more is evaluated as wood destruction.

A lower active ingredient concentration at which the wood just begins tobe destroyed and an upper active ingredient concentration at which nowood destruction is detectable and hence complete wood preservation hasbeen achieved are stated. It is always necessary to start from the upperactive ingredient concentration for evaluating a wood preservative inpractice.

The determination of the limit of the action against wood-destroyingfungi (in kg of active ingredient or mixture of active ingredients perm³ of wood)

The result should be understood as follows. The lower the limit, thebetter the fungicidal action. 1 kg/m³ is thus better than 2 kg/m³.

EXAMPLE A (Not According to the Invention)

20% by weight of Cu(OH)₂CuCO₃ 45% by weight of monoethanolamine 10% byweight of boric acid 25% by weight of water

Limit with respect to the wood-destroying Basidiomycetes Coniophoraputeana and Poria placenta: more than 35 kg/m³.

EXAMPLE B (Not According to the Invention)

17.5% of Cu(OH)₂.CuCO₃   42% of monoethanolamine   30% of boric acid10.5% of water

Limit with respect to Coniphora puteana and Poria placenta: more than 35kg/M³.

EXAMPLE C (Not According to the Invention)

Limits for triazole compounds dissolved in acetone

Azaconazole Propiconazole Coniophora puteana 2.8 to 5.7 0.21 to 0.33kg/m³ Poria placenta 0.9 to 1.5 0.57 to 0.91 kg/m³

EXAMPLE D (Not According to the Invention)

50% n-tributyltetradecylphosphonium chloride (commercial) dissolved inwater

Limits Coniophora puteana 7.7 to 12.3 kg/m³ Poria placenta 4.7 to 7.3kg/m³

EXAMPLE 1

14.0% of Cu(OH)₂CuCO₃ 33.5% of monoethanolamine 7.5% of boric acid 6.0%of propionic acid 19.0% of water 4.0% of propiconazole 10.0% ofethoxylated nonylphenol (10 units of ethylene oxide per nonylphenol unit= EO 10) 6.0% of propylene glycol

Limits Coniophora puteana 3.0 to 4.7 kg/m³ Poria placenta 4.7 to 7.3kg/m³

EXAMPLE 2

14.0% of Cu(OH)₂CuCO₃ 33.5% of monoethanolamine 22.0% of boric acid10.5% of water  4.0% of propiconazole 10.0% of ethoxylated nonylphenol 6.0% of propylene glycol

Limits Coniophora puteana 4.6 to 7.2 kg/m³ Poria placenta 4.7 to 7.3kg/m³

EXAMPLE 3

14.0% of Cu(OH)₂CuCO₃ 33.5% of monoethanolamine 22.0% of benzoic acid10.5% of water  2.5% of propiconazole  1.5% of azaconazole 10.0% ofethoxylated nonylphenol  6.0% of propylene glycol

Limits Coniophora puteana 4.6 to 7.2 kg/m³ Poria placenta 7.3 to 11.2kg/m³

EXAMPLE 4

14.0% of Cu(OH)₂CuCO₃ 27.0% of monoethanolamine  7.5% of polymin n = 15021.0% of benzoic acid 14.0% of water  4.0% of propiconazole 10.0% ofethoxylated nonylphenol  9.0% of propylene glycol

Limits Coniophora puteana 3.4 to 4.6 kg/m³ Poria placenta 4.6 to 7.2kg/m³

EXAMPLE 5

13% of Cu(OH)₂CuCO₃ 31% of monoethanolamine 20% of benzoic acid 23% ofwater 13% of tri-n-butyltetradecylphosphonium chloride

Limits Coniophora puteana 11.4 to 18.3 kg/m³ Poria placenta 11.5 to 18.1kg/m³

We claim:
 1. A wood preservative containing 2.5 to 45% by weight of acopper compound and 5 to 50% by weight of an alkanolamine, which woodpreservative additionally contains 0.25 to 15% by weight ofcyproconazole and 0.5 to 30% by weight of an emulsifier.
 2. A method ofpreserving wood, wherein the wood is treated with an effective amount ofa wood preservative as claimed in claim 1.